Core: Migrate @storybook/core-server to strict TypeScript

code/lib/core-server/src/build-dev.ts

@@ -14,6 +14,7 @@ import {
   validateFrameworkName,
 } from '@storybook/core-common';
 import prompts from 'prompts';
+import invariant from 'tiny-invariant';
 import { global } from '@storybook/global';
 import { telemetry } from '@storybook/telemetry';
 
@@ -31,7 +32,7 @@ export async function buildDevStandalone(
 ): Promise<{ port: number; address: string; networkAddress: string }> {
   const { packageJson, versionUpdates } = options;
   const { version } = packageJson;
-
+  invariant(version !== undefined, 'Expected package.json version to be defined.');
   // updateInfo are cached, so this is typically pretty fast
   const [port, versionCheck] = await Promise.all([
     getServerPort(options.port),
@@ -63,9 +64,10 @@ export async function buildDevStandalone(
 
   const config = await loadMainConfig(options);
   const { framework } = config;
+  invariant(framework, 'framework is required in Storybook v7');
   const corePresets = [];
 
-  const frameworkName = typeof framework === 'string' ? framework : framework?.name;
+  const frameworkName = typeof framework === 'string' ? framework : framework.name;
   validateFrameworkName(frameworkName);
 
   corePresets.push(join(frameworkName, 'preset'));
@@ -82,30 +84,34 @@ export async function buildDevStandalone(
   });
 
   const { renderer, builder, disableTelemetry } = await presets.apply<CoreConfig>('core', {});
+  invariant(builder, 'no builder configured!');
 
   if (!options.disableTelemetry && !disableTelemetry) {
     if (versionCheck.success && !versionCheck.cached) {
       telemetry('version-update');
     }
   }
 
-  const builderName = typeof builder === 'string' ? builder : builder?.name;
+  const builderName = typeof builder === 'string' ? builder : builder.name;
   const [previewBuilder, managerBuilder] = await Promise.all([
     getPreviewBuilder(builderName, options.configDir),
     getManagerBuilder(),
   ]);
 
+  const resolvedRenderer = renderer
+    ? resolveAddonName(options.configDir, renderer, options)
+    : undefined;
   // Load second pass: all presets are applied in order
   presets = await loadAllPresets({
     corePresets: [
       require.resolve('@storybook/core-server/dist/presets/common-preset'),
       ...(managerBuilder.corePresets || []),
       ...(previewBuilder.corePresets || []),
-      ...(renderer ? [resolveAddonName(options.configDir, renderer, options)] : []),
+      ...(resolvedRenderer ? [resolvedRenderer] : []),
       ...corePresets,
       require.resolve('@storybook/core-server/dist/presets/babel-cache-preset'),
     ],
-    overridePresets: previewBuilder.overridePresets,
+    overridePresets: previewBuilder.overridePresets ?? [],
     ...options,
   });
 
@@ -123,8 +129,7 @@ export async function buildDevStandalone(
   );
 
   const previewTotalTime = previewResult && previewResult.totalTime;
-  const managerTotalTime = managerResult && managerResult.totalTime;
-
+  const managerTotalTime = managerResult ? managerResult.totalTime : undefined;
   const previewStats = previewResult && previewResult.stats;
   const managerStats = managerResult && managerResult.stats;
 

code/lib/core-server/src/build-static.ts

@@ -91,13 +91,15 @@ export async function buildStaticStandalone(options: BuildStaticStandaloneOption
 
   const [previewBuilder, managerBuilder] = await getBuilders({ ...options, presets });
   const { renderer } = await presets.apply<CoreConfig>('core', {});
-
+  const resolvedRenderer = renderer
+    ? resolveAddonName(options.configDir, renderer, options)
+    : undefined;
   presets = await loadAllPresets({
     corePresets: [
       require.resolve('@storybook/core-server/dist/presets/common-preset'),
       ...(managerBuilder.corePresets || []),
       ...(previewBuilder.corePresets || []),
-      ...(renderer ? [resolveAddonName(options.configDir, renderer, options)] : []),
+      ...(resolvedRenderer ? [resolvedRenderer] : []),
       ...corePresets,
       require.resolve('@storybook/core-server/dist/presets/babel-cache-preset'),
     ],
@@ -151,7 +153,8 @@ export async function buildStaticStandalone(options: BuildStaticStandaloneOption
   );
   effects.push(copy(coreServerPublicDir, options.outputDir));
 
-  let initializedStoryIndexGenerator: Promise<StoryIndexGenerator> = Promise.resolve(undefined);
+  let initializedStoryIndexGenerator: Promise<StoryIndexGenerator | undefined> =
+    Promise.resolve(undefined);
   if ((features?.buildStoriesJson || features?.storyStoreV7) && !options.ignorePreview) {
     const workingDir = process.cwd();
     const directories = {
@@ -167,17 +170,21 @@ export async function buildStaticStandalone(options: BuildStaticStandaloneOption
       storyStoreV7: !!features?.storyStoreV7,
     });
 
-    initializedStoryIndexGenerator = generator.initialize().then(() => generator);
+    const initializedStoryIndexGeneratorPromise = generator.initialize().then(() => generator);
     effects.push(
       extractStoriesJson(
         join(options.outputDir, 'stories.json'),
-        initializedStoryIndexGenerator,
+        initializedStoryIndexGeneratorPromise,
         convertToIndexV3
       )
     );
     effects.push(
-      extractStoriesJson(join(options.outputDir, 'index.json'), initializedStoryIndexGenerator)
+      extractStoriesJson(
+        join(options.outputDir, 'index.json'),
+        initializedStoryIndexGeneratorPromise
+      )
     );
+    initializedStoryIndexGenerator = initializedStoryIndexGeneratorPromise;
   }
 
   if (!core?.disableProjectJson) {

code/lib/core-server/src/dev-server.ts

@@ -1,5 +1,6 @@
 import express from 'express';
 import compression from 'compression';
+import invariant from 'tiny-invariant';
 
 import type { CoreConfig, Options, StorybookConfig } from '@storybook/types';
 
@@ -34,31 +35,29 @@ export async function storybookDevServer(options: Options) {
     getServerChannel(server)
   );
 
-  let indexError: Error;
+  let indexError: Error | undefined;
   // try get index generator, if failed, send telemetry without storyCount, then rethrow the error
-  const initializedStoryIndexGenerator: Promise<StoryIndexGenerator> = getStoryIndexGenerator(
-    features,
-    options,
-    serverChannel
-  ).catch((err) => {
-    indexError = err;
-    return undefined;
-  });
+  const initializedStoryIndexGenerator: Promise<StoryIndexGenerator | undefined> =
+    getStoryIndexGenerator(features ?? {}, options, serverChannel).catch((err) => {
+      indexError = err;
+      return undefined;
+    });
 
   app.use(compression({ level: 1 }));
 
   if (typeof options.extendServer === 'function') {
     options.extendServer(server);
   }
 
-  app.use(getAccessControlMiddleware(core?.crossOriginIsolated));
+  app.use(getAccessControlMiddleware(core?.crossOriginIsolated ?? false));
   app.use(getCachingMiddleware());
 
   getMiddleware(options.configDir)(router);
 
   app.use(router);
 
   const { port, host, initialPath } = options;
+  invariant(port, 'expected options to have a port');
   const proto = options.https ? 'https' : 'http';
   const { address, networkAddress } = getServerAddresses(port, host, proto, initialPath);
 
@@ -67,6 +66,7 @@ export async function storybookDevServer(options: Options) {
     server.listen({ port, host }, (error: Error) => (error ? reject(error) : resolve()));
   });
 
+  invariant(core?.builder, 'no builder configured!');
   const builderName = typeof core?.builder === 'string' ? core.builder : core?.builder?.name;
 
   const [previewBuilder, managerBuilder] = await Promise.all([

code/lib/core-server/src/presets/common-preset.ts

@@ -44,7 +44,7 @@ export const staticDirs: PresetPropertyFn<'staticDirs'> = async (values = []) =>
 ];
 
 export const favicon = async (
-  value: string,
+  value: string | undefined,
   options: Pick<Options, 'presets' | 'configDir' | 'staticDir'>
 ) => {
   if (value) {
@@ -257,8 +257,13 @@ type WhatsNewResponse = {
   excerpt: string;
 };
 
+type OptionsWithRequiredCache = Exclude<Options, 'cache'> & Required<Pick<Options, 'cache'>>;
+
 // eslint-disable-next-line @typescript-eslint/naming-convention
-export const experimental_serverChannel = async (channel: Channel, options: Options) => {
+export const experimental_serverChannel = async (
+  channel: Channel,
+  options: OptionsWithRequiredCache
+) => {
   const coreOptions = await options.presets.apply('core');
 
   channel.on(SET_WHATS_NEW_CACHE, async (data: WhatsNewCache) => {
@@ -277,7 +282,10 @@ export const experimental_serverChannel = async (channel: Channel, options: Opti
         throw response;
       })) as WhatsNewResponse;
 
-      const main = await readConfig(findConfigFile('main', options.configDir));
+      const configFileName = findConfigFile('main', options.configDir);
+      if (!configFileName)
+        throw new Error(`unable to find storybook main file in ${options.configDir}`);
+      const main = await readConfig(configFileName);
       const disableWhatsNewNotifications = main.getFieldValue([
         'core',
         'disableWhatsNewNotifications',
@@ -293,7 +301,7 @@ export const experimental_serverChannel = async (channel: Channel, options: Opti
       } satisfies WhatsNewData;
       channel.emit(RESULT_WHATS_NEW_DATA, { data });
     } catch (e) {
-      logger.verbose(e);
+      logger.verbose(e instanceof Error ? e.message : String(e));
       channel.emit(RESULT_WHATS_NEW_DATA, {
         data: { status: 'ERROR' } satisfies WhatsNewData,
       });
@@ -305,7 +313,10 @@ export const experimental_serverChannel = async (channel: Channel, options: Opti
     async ({ disableWhatsNewNotifications }: { disableWhatsNewNotifications: boolean }) => {
       const isTelemetryEnabled = coreOptions.disableTelemetry !== true;
       try {
-        const main = await readConfig(findConfigFile('main', options.configDir));
+        const configFileName = findConfigFile('main', options.configDir);
+        if (!configFileName)
+          throw new Error(`unable to find storybook main file in ${options.configDir}`);
+        const main = await readConfig(configFileName);
         main.setFieldValue(['core', 'disableWhatsNewNotifications'], disableWhatsNewNotifications);
         await writeConfig(main);
 
@@ -314,7 +325,7 @@ export const experimental_serverChannel = async (channel: Channel, options: Opti
         }
       } catch (error) {
         if (isTelemetryEnabled) {
-          await sendTelemetryError(error, 'core-config', {
+          await sendTelemetryError(error as Error, 'core-config', {
             cliOptions: options,
             presetOptions: { ...options, corePresets: [], overridePresets: [] },
             skipPrompt: true,

code/lib/core-server/src/standalone.ts

@@ -4,7 +4,7 @@ import { buildDevStandalone } from './build-dev';
 
 async function build(options: any = {}, frameworkOptions: any = {}) {
   const { mode = 'dev' } = options;
-  const { packageJson } = readUpSync({ cwd: __dirname });
+  const packageJson = readUpSync({ cwd: __dirname })?.packageJson;
 
   const commonOptions = {
     ...options,